Holding device for instruments.



G. W. DUNHAM.

HOLDING DEVICE FOR INSTRUMENTS APPLICATION FILED FBB.24,1914

1 1 20 ,040, Patented Dec. 8, 1914.

WITNESSES INVENTOR 04 MM ifiz Q11, $1M

UNITED STATES PATENT OFFICE.

CHARLES W. DUNHAM, 0F SWISSVALE, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF S\VISSVALE; PENNSLVANIA, A CORPORATION OF PENNSYLVANIA.

HOLDING DEVICE FOR INSTRUMENTS.

Specification of Letters Patent.

Patented Dec. 8, 1914.

Application filed February 24, 1914. 'Serial No. 820,724.

T 0 all whom it may concern:

Be it known that I, CHARLES 'W. DUNHAM, a citizen of the United States, residing at Swissvale, in the county of Allegheny and State of Pennsylvania, have invented certuin new and useful Improvements in Holding Devices for Instruments, of which the following is a specification.

My invention relates to instruments having delicate movable members, and particularl v to means for protecting the movable members of such instruments from injury due to jar or shock during shipment.

My invention is particularly well adapted for use with electrical. instruments, such as relays, comprising a movable member trolled thereby.

One feature of my invention is the {no vision of means for holding the movable iember in an intermediate position in which, in the case of a relay, the contact fingers are disengaged from the contact members with which they coiiperate, so that the adjustment of the fingers cannot be and delicately adjusted contact fingers conderanged during shipment, and also so thatv in case the instrument is installed without removing the protecting means, all circuits controlled by the instrument will be open.

I will describe one form of relay having applied thereto one form of protecting means embodying my invention and will then point out the novel features thereof in claims.

In the accompanying drawings, Figure 1 is a view showing in side elevation, partly sectioned, one form of relay having applied thereto qne form of protecting device embodying my invention, and Fig. 2 is a view showing on a larger scale the screw 11 shown in Fig. 1.

Similar reference characters refer to similar parts in both views.

Referring first to Fig. 1, the relay here shown comprisesa top plate 3 in which is mounted an electromagnet 1 whose polepieces 4 are'located on the under side of the top plate. The pole-pieces carry brackets 5 in which is journaled an armature 2 adapt ed to be attracted toward the pole-pieces when the magnet 1 is energized, and to fall away therefrom by gravity when the magnet is not energized. Fixed to the armature 2 are studs 6 of insulating material which carry contact-springs'7, only one of which is shown in the drawing. This spring 7 carries a contact finger 7" which is adapted to make and break contact with a fixed Contact member 8 mounted in the top pinto 3, and it also carries another contact finger T -which is adapted to make and break contact with another fixed contact member 8" also mounted in top plate 3. It is understood that the upper contact 7*8* is closedwhen the armatureQ is attracted to the pole pieces, and that the lower contact T e??? is closed when the armature falls away from the pole-pieces The armature and contacts are inclosed in a casing comprising the top plate 3, a bottom plate 9, and a glass ring 10.

The contact fingers T and 8 are delicately adjusted when the relay is assembled. and unless some protecting device is provided this adjustment is apt to be destroyed by jars and shocks during shipment. The protecting device here shown is .a screw 11 which is shown on a larger. scale .in Fig.2.

that of portion 13, that is, there are more threads per inch in portion 1'2 than in por tion 13. Since the threaded portion 12 and the middle unthreaded portion of the screw are smaller in diameter than the portion 1-3, the first two portions will through the hole 11 in the bottom plate. Thelarger end of the screw is preferably provided with a 'slot 11 to accommodate a screw driver.

The operation of the screw 11 is as follows: After the relay has been assembled, the screw is passed upwardly through-the hole 14 and is turned a short distance into hole 15 in the armature, the armature being at its lowest position, that is. farthest away from the pole-pieces {1. The length of the middle unthreaded portion is such pass freely that when this has been done the threads 13 begin to catch in the threads of hole 14;.- As the turning is continued, the screw at i vances into b'oth "the 'jarmature and the bot-. tom plate, but owing to. the difi'ereneo in pitches of the threads it advances -more slowly into the armature than into the bottom plate, sov that the armature is raised toward the pole-pieces. The turning is continued until the armature is suspended midway between'its extreme positions, so'that both contacts 7---8 and FfB are open, and the screw is then looked in position bya'nut'17."

The hole 15 in the armature is preferably slightly'larger than the threaded portion 12 of-the screw, to permit the armature to swing on its pivot without causing the screw tobind.-

It will be seen that during shipment there is no possibility of derangement of the adjustment of contact fingers 7 and? because if i's impossible for these fingers to be iarred intoengagementwith member 8 or 8'2. It

also be" seen that when the relay is installed in service, ifthe screw 11' is not re mowfedf'allfcireuits controlled by the relay win =iremai1; ope'nand no damage can residtt lhis featuref-is of particular importanoe'in t he ease of-relays employed in railway signaiing, because if the screw is not removed; a false-bleak signal cannot be caused-, as has sometimes been the case when protective [devices have been employed which hold the armature rigid with one set of contacts closedduring shipment.

If' desired, the arrangement 0f screw threadson screw 11 may be reversed, the threads which enter the armature being of pitch than' those which screw into the hottom plate. Then 'in applying the screw"th ej armature would be pressed up against-the ole-pieces before starting the screw in the" ttom plate, and the armature would be drawn away from the polepieces because the screw would travel faster in the armature than'in the bottom plate. The arrangement shown in the drawings is, howevergreferable because if the armature is forc too far by the screw it will be stopped by the pole-pieces and no harm will be done to the contacts, whereas with the alternative arrangement if the armatureishouid be forced too far the spring 7 or'thelower finger 7 would be bent.

Although I have shown and described only one form of protective device embodymg my invention, it is understood that mam changes and modifications may be inside therein within the scope of the appendmpclaims without departingfrom the scope of my invention.

Having thus described my invention, what I claim is:

1.. In combination, an instrument having a movable member, an inclosing casing for said movable member, and means proiecting into'said casing for locking said morable member in an'intermediate position.

2. Incombination, an instrument having a movable member, aninclosing casing for said movable member, wscrew having two threaded'portions of different pitches, a hole in the movable'member provided with threads of the same pitch as those on one portion of the screw,'and a hole in the casing provided with threads of the same pitch as those on'the other portion of the screw.

3. In combination, an instrument having a movable member,- an inclosing casing for said "movable member, a screw having two threaded portions of different diameters and different pitches, a hole in the movable member provided with screw threads of substantially the -same diameter and the same pitch as those on the smaller portion of the screw, and a hole in the casing provided with screw threads of the same diam eter and same pitch as those on the larger portion of the screw. 4. In combination, an instrument comprising a' movable member and contacts one of which is closed when the member occupies one position and another of which is closed when the member occupies another position, and means for locking said mem her in an intermediate position in which both contacts areopen.

5. In combination, an instrument having a fixed part and a movable member, and means for locking said movable member to the fixed part in an intermediate position.

6. In combination, an instrument having a fixed part and a movable member,a screw having two threaded portions of different pitches, threads associated with the movable member and having the same pitch as those on one portion of the screw, and threads associated with the fixed part and having the same pitch as those on the other portion of the screw.

7. In combination, an instrument having a fixed part and a movable member, a screw, a hole in the fixed member provided with threads matching those on the screw, and

means for loclrlng the movable member to the screw.

In testimony whereof I aiiix my signature in presence of two witnesses.

I CHARLES W. DUNHAM.

Vitnesses:

A. HERMAN Wnoma, R. L. Krs'rnna. 

